If we are going to put in a goblin producing building I think we might assign units production more based on race than role (except for casters that will all will continue belonging to the shaman's hut unless we wanna redescuss that too)

So basically my idea is:

Orc tent: produce all orc units included orc cavalry (cavalry techs will still remain at the monster cave since is where mounts will come from)

Goblin tent: same as orc tent

Uruk tent: as it is

Monster cave: will produce giants, trolls, minotaurs and other monter-like creatures (unless we plan to make a new building for more troll units)

Techs:

orc cavalry: at monster cave

giant tech: monster cave

troll upgrades: monster cave

uruk upgrades: uruk tent

Orc upgrades, orc skin and so on: orc tent

goblin upgrades, goblin shout and so on: goblin tent

All or some of those techs might stay at tc too (otherwise tcs could never research techs since orc techs are all race-based)